If Quick Build isn't allowed to break the Solitary rule of one per list, you can't fly two Belbullabs together unless one is the elite generic, since they all have Tactical Relays.
And if it *does* break the rule, that opens up a whole can of worms: what's next, two copies of Grievous, etc. in a list? (Hey, if Solitary is ignored, it stands to reason uniqueness would be as well!)